/**
 * @ignore
 * Find more about the scrolling function at
 * http://cubiq.org/iscroll
 *
 * Copyright (c) 2010 Matteo Spinelli, http://cubiq.org/
 * Released under MIT license
 * http://cubiq.org/dropbox/mit-license.txt
 *
 * Version 3.7.1 - Last updated: 2010.10.08
 *
 */

(function() {
	function iScroll(el, options) {
		var that = this, i;
		that.element = typeof el == 'object' ? el : document.getElementById(el);
		that.wrapper = that.element.parentNode;

		that.element.style.webkitTransitionProperty = '-webkit-transform';
		that.element.style.webkitTransitionTimingFunction = 'cubic-bezier(0,0,0.25,1)';
		that.element.style.webkitTransitionDuration = '0';
		that.element.style.webkitTransform = translateOpen + '0,0' + translateClose;

		// Default options
		that.options = {
			bounce : has3d,
			momentum : has3d,
			checkDOMChanges : true,
			topOnDOMChanges : false,
			hScrollbar : has3d,
			vScrollbar : has3d,
			fadeScrollbar : isIthing || !isTouch,
			shrinkScrollbar : isIthing || !isTouch,
			desktopCompatibility : false,
			overflow : 'auto',
			snap : false,
			bounceLock : false,
			scrollbarColor : 'rgba(0,0,0,0.5)',
			onScrollEnd : function() {
			}
		};

		// User defined options
		if( typeof options == 'object') {
			for(i in options) {
				that.options[i] = options[i];
			}
		}

		if(that.options.desktopCompatibility) {
			that.options.overflow = 'hidden';
		}

		that.onScrollEnd = that.options.onScrollEnd;
		delete that.options.onScrollEnd;

		that.wrapper.style.overflow = that.options.overflow;

		that.refresh();

		window.addEventListener('onorientationchange' in window ? 'orientationchange' : 'resize', that, false);

		if(isTouch || that.options.desktopCompatibility) {
			that.element.addEventListener(START_EVENT, that, false);
			that.element.addEventListener(MOVE_EVENT, that, false);
			that.element.addEventListener(END_EVENT, that, false);
		}

		if(that.options.checkDOMChanges) {
			that.element.addEventListener('DOMSubtreeModified', that, false);
		}
	}


	iScroll.prototype = {
		x : 0,
		y : 0,
		enabled : true,

		handleEvent : function(e) {
			var that = this;

			switch (e.type) {
				case START_EVENT:
					that.touchStart(e);
					break;
				case MOVE_EVENT:
					that.touchMove(e);
					break;
				case END_EVENT:
					that.touchEnd(e);
					break;
				case 'webkitTransitionEnd':
					that.transitionEnd();
					break;
				case 'orientationchange':
				case 'resize':
					that.refresh();
					break;
				case 'DOMSubtreeModified':
					that.onDOMModified(e);
					break;
			}
		},
		onDOMModified : function(e) {
			var that = this;

			// (Hopefully) execute onDOMModified only once
			if(e.target.parentNode != that.element) {
				return;
			}

			setTimeout(function() {
				that.refresh();
			}, 0);
			if(that.options.topOnDOMChanges && (that.x != 0 || that.y != 0)) {
				that.scrollTo(0, 0, '0');
			}
		},
		refresh : function() {
			var that = this, resetX = that.x, resetY = that.y, snap;

			that.scrollWidth = that.wrapper.clientWidth;
			that.scrollHeight = that.wrapper.clientHeight;
			that.scrollerWidth = that.element.offsetWidth;
			that.scrollerHeight = that.element.offsetHeight;
			that.maxScrollX = that.scrollWidth - that.scrollerWidth;
			that.maxScrollY = that.scrollHeight - that.scrollerHeight;
			that.directionX = 0;
			that.directionY = 0;

			if(that.scrollX) {
				if(that.maxScrollX >= 0) {
					resetX = 0;
				} else if(that.x < that.maxScrollX) {
					resetX = that.maxScrollX;
				}
			}
			if(that.scrollY) {
				if(that.maxScrollY >= 0) {
					resetY = 0;
				} else if(that.y < that.maxScrollY) {
					resetY = that.maxScrollY;
				}
			}

			// Snap
			if(that.options.snap) {
				that.maxPageX = -Math.floor(that.maxScrollX / that.scrollWidth);
				that.maxPageY = -Math.floor(that.maxScrollY / that.scrollHeight);
				snap = that.snap(resetX, resetY);
				resetX = snap.x;
				resetY = snap.y;
			}

			if(resetX != that.x || resetY != that.y) {
				that.setTransitionTime('0');
				that.setPosition(resetX, resetY, true);
			}

			that.scrollX = that.scrollerWidth > that.scrollWidth;
			that.scrollY = !that.options.bounceLock && !that.scrollX || that.scrollerHeight > that.scrollHeight;

			// Update horizontal scrollbar
			if(that.options.hScrollbar && that.scrollX) {
				that.scrollBarX = that.scrollBarX || new scrollbar('horizontal', that.wrapper, that.options.fadeScrollbar, that.options.shrinkScrollbar, that.options.scrollbarColor);
				that.scrollBarX.init(that.scrollWidth, that.scrollerWidth);
			} else if(that.scrollBarX) {
				that.scrollBarX = that.scrollBarX.remove();
			}

			// Update vertical scrollbar
			if(that.options.vScrollbar && that.scrollY && that.scrollerHeight > that.scrollHeight) {
				that.scrollBarY = that.scrollBarY || new scrollbar('vertical', that.wrapper, that.options.fadeScrollbar, that.options.shrinkScrollbar, that.options.scrollbarColor);
				that.scrollBarY.init(that.scrollHeight, that.scrollerHeight);
			} else if(that.scrollBarY) {
				that.scrollBarY = that.scrollBarY.remove();
			}
		},
		setPosition : function(x, y, hideScrollBars) {
			var that = this;

			that.x = x;
			that.y = y;

			that.element.style.webkitTransform = translateOpen + that.x + 'px,' + that.y + 'px' + translateClose;

			// Move the scrollbars
			if(!hideScrollBars) {
				if(that.scrollBarX) {
					that.scrollBarX.setPosition(that.x);
				}
				if(that.scrollBarY) {
					that.scrollBarY.setPosition(that.y);
				}
			}
		},
		setTransitionTime : function(time) {
			var that = this;
			time = time || '0';
			that.element.style.webkitTransitionDuration = time;

			if(that.scrollBarX) {
				that.scrollBarX.bar.style.webkitTransitionDuration = time;
				that.scrollBarX.wrapper.style.webkitTransitionDuration = has3d && that.options.fadeScrollbar ? '300ms' : '0';
			}
			if(that.scrollBarY) {
				that.scrollBarY.bar.style.webkitTransitionDuration = time;
				that.scrollBarY.wrapper.style.webkitTransitionDuration = has3d && that.options.fadeScrollbar ? '300ms' : '0';
			}
		},
		touchStart : function(e) {
			var that = this, matrix;

			if(!that.enabled) {
				return;
			}

			e.preventDefault();
			e.stopPropagation();

			that.scrolling = true;
			// This is probably not needed, but may be useful if iScroll is used in conjuction with other frameworks

			that.moved = false;
			that.distX = 0;
			that.distY = 0;

			that.setTransitionTime('0');

			// Check if the scroller is really where it should be
			if(that.options.momentum || that.options.snap) {
				matrix = new WebKitCSSMatrix(window.getComputedStyle(that.element).webkitTransform);
				if(matrix.e != that.x || matrix.f != that.y) {
					document.removeEventListener('webkitTransitionEnd', that, false);
					that.setPosition(matrix.e, matrix.f);
					that.moved = true;
				}
			}

			that.touchStartX = isTouch ? e.changedTouches[0].pageX : e.pageX;
			that.scrollStartX = that.x;

			that.touchStartY = isTouch ? e.changedTouches[0].pageY : e.pageY;
			that.scrollStartY = that.y;

			that.scrollStartTime = e.timeStamp;

			that.directionX = 0;
			that.directionY = 0;
		},
		touchMove : function(e) {
			if(!this.scrolling) {
				return;
			}

			var that = this, pageX = isTouch ? e.changedTouches[0].pageX : e.pageX, pageY = isTouch ? e.changedTouches[0].pageY : e.pageY, leftDelta = that.scrollX ? pageX - that.touchStartX : 0, topDelta = that.scrollY ? pageY - that.touchStartY : 0, newX = that.x + leftDelta, newY = that.y + topDelta;

			//e.preventDefault();
			e.stopPropagation();
			// Stopping propagation just saves some cpu cycles (I presume)

			that.touchStartX = pageX;
			that.touchStartY = pageY;

			// Slow down if outside of the boundaries
			if(newX >= 0 || newX < that.maxScrollX) {
				newX = that.options.bounce ? Math.round(that.x + leftDelta / 3) : (newX >= 0 || that.maxScrollX >= 0) ? 0 : that.maxScrollX;
			}
			if(newY >= 0 || newY < that.maxScrollY) {
				newY = that.options.bounce ? Math.round(that.y + topDelta / 3) : (newY >= 0 || that.maxScrollY >= 0) ? 0 : that.maxScrollY;
			}

			if(that.distX + that.distY > 5) {// 5 pixels threshold

				// Lock scroll direction
				if(that.distX - 3 > that.distY) {
					newY = that.y;
					topDelta = 0;
				} else if(that.distY - 3 > that.distX) {
					newX = that.x;
					leftDelta = 0;
				}

				that.setPosition(newX, newY);
				that.moved = true;
				that.directionX = leftDelta > 0 ? -1 : 1;
				that.directionY = topDelta > 0 ? -1 : 1;
			} else {
				that.distX += Math.abs(leftDelta);
				that.distY += Math.abs(topDelta);
				//			that.dist+= Math.abs(leftDelta) + Math.abs(topDelta);
			}
		},
		touchEnd : function(e) {
			if(!this.scrolling) {
				return;
			}

			var that = this, time = e.timeStamp - that.scrollStartTime, point = isTouch ? e.changedTouches[0] : e, target, ev, momentumX, momentumY, newDuration = 0, newPositionX = that.x, newPositionY = that.y, snap;

			that.scrolling = false;

			if(!that.moved) {
				that.resetPosition();

				if(isTouch) {
					// Find the last touched element
					target = point.target;
					while(target.nodeType != 1) {
						target = target.parentNode;
					}

					// Create the fake event
					ev = document.createEvent('MouseEvents');
					ev.initMouseEvent('click', true, true, e.view, 1, point.screenX, point.screenY, point.clientX, point.clientY, e.ctrlKey, e.altKey, e.shiftKey, e.metaKey, 0, null);
					ev._fake = true;
					target.dispatchEvent(ev);
				}

				return;
			}

			if(!that.options.snap && time > 250) {// Prevent slingshot effect
				that.resetPosition();
				return;
			}

			if(that.options.momentum) {
				momentumX = that.scrollX === true ? that.momentum(that.x - that.scrollStartX, time, that.options.bounce ? -that.x + that.scrollWidth / 5 : -that.x, that.options.bounce ? that.x + that.scrollerWidth - that.scrollWidth + that.scrollWidth / 5 : that.x + that.scrollerWidth - that.scrollWidth) : {
					dist : 0,
					time : 0
				};
				momentumY = that.scrollY === true ? that.momentum(that.y - that.scrollStartY, time, that.options.bounce ? -that.y + that.scrollHeight / 5 : -that.y, that.options.bounce ? (that.maxScrollY < 0 ? that.y + that.scrollerHeight - that.scrollHeight : 0) + that.scrollHeight / 5 : that.y + that.scrollerHeight - that.scrollHeight) : {
					dist : 0,
					time : 0
				};
				newDuration = Math.max(Math.max(momentumX.time, momentumY.time), 1);
				// The minimum animation length must be 1ms
				newPositionX = that.x + momentumX.dist;
				newPositionY = that.y + momentumY.dist;
			}

			if(that.options.snap) {
				snap = that.snap(newPositionX, newPositionY);
				newPositionX = snap.x;
				newPositionY = snap.y;
				newDuration = Math.max(snap.time, newDuration);
			}

			that.scrollTo(newPositionX, newPositionY, newDuration + 'ms');
		},
		transitionEnd : function() {
			var that = this;
			document.removeEventListener('webkitTransitionEnd', that, false);
			that.resetPosition();
		},
		resetPosition : function() {
			var that = this, resetX = that.x, resetY = that.y;

			if(that.x >= 0) {
				resetX = 0;
			} else if(that.x < that.maxScrollX) {
				resetX = that.maxScrollX;
			}

			if(that.y >= 0 || that.maxScrollY > 0) {
				resetY = 0;
			} else if(that.y < that.maxScrollY) {
				resetY = that.maxScrollY;
			}

			if(resetX != that.x || resetY != that.y) {
				that.scrollTo(resetX, resetY);
			} else {
				if(that.moved) {
					that.onScrollEnd();
					// Execute custom code on scroll end
					that.moved = false;
				}

				// Hide the scrollbars
				if(that.scrollBarX) {
					that.scrollBarX.hide();
				}
				if(that.scrollBarY) {
					that.scrollBarY.hide();
				}
			}
		},
		snap : function(x, y) {
			var that = this, time;

			if(that.directionX > 0) {
				x = Math.floor(x / that.scrollWidth);
			} else if(that.directionX < 0) {
				x = Math.ceil(x / that.scrollWidth);
			} else {
				x = Math.round(x / that.scrollWidth);
			}
			that.pageX = -x;
			x = x * that.scrollWidth;
			if(x > 0) {
				x = that.pageX = 0;
			} else if(x < that.maxScrollX) {
				that.pageX = that.maxPageX;
				x = that.maxScrollX;
			}

			if(that.directionY > 0) {
				y = Math.floor(y / that.scrollHeight);
			} else if(that.directionY < 0) {
				y = Math.ceil(y / that.scrollHeight);
			} else {
				y = Math.round(y / that.scrollHeight);
			}
			that.pageY = -y;
			y = y * that.scrollHeight;
			if(y > 0) {
				y = that.pageY = 0;
			} else if(y < that.maxScrollY) {
				that.pageY = that.maxPageY;
				y = that.maxScrollY;
			}

			// Snap with constant speed (proportional duration)
			time = Math.round(Math.max(Math.abs(that.x - x) / that.scrollWidth * 500, Math.abs(that.y - y) / that.scrollHeight * 500));

			return {
				x : x,
				y : y,
				time : time
			};
		},
		scrollTo : function(destX, destY, runtime) {
			var that = this;

			if(that.x == destX && that.y == destY) {
				that.resetPosition();
				return;
			}

			that.moved = true;
			that.setTransitionTime(runtime || '350ms');
			that.setPosition(destX, destY);

			if(runtime === '0' || runtime == '0s' || runtime == '0ms') {
				that.resetPosition();
			} else {
				document.addEventListener('webkitTransitionEnd', that, false);
				// At the end of the transition check if we are still inside of the boundaries
			}
		},
		scrollToPage : function(pageX, pageY, runtime) {
			var that = this, snap;

			if(!that.options.snap) {
				that.pageX = -Math.round(that.x / that.scrollWidth);
				that.pageY = -Math.round(that.y / that.scrollHeight);
			}

			if(pageX == 'next') {
				pageX = ++that.pageX;
			} else if(pageX == 'prev') {
				pageX = --that.pageX;
			}

			if(pageY == 'next') {
				pageY = ++that.pageY;
			} else if(pageY == 'prev') {
				pageY = --that.pageY;
			}
			pageX = -pageX * that.scrollWidth;
			pageY = -pageY * that.scrollHeight;
			snap = that.snap(pageX, pageY);
			pageX = snap.x;
			pageY = snap.y;

			that.scrollTo(pageX, pageY, runtime || '500ms');
		},
		scrollToElement : function(el, runtime) {
			el = typeof el == 'object' ? el : this.element.querySelector(el);

			if(!el) {
				return;
			}

			var that = this, x = that.scrollX ? -el.offsetLeft : 0, y = that.scrollY ? -el.offsetTop : 0;

			if(x >= 0) {
				x = 0;
			} else if(x < that.maxScrollX) {
				x = that.maxScrollX;
			}

			if(y >= 0) {
				y = 0;
			} else if(y < that.maxScrollY) {
				y = that.maxScrollY;
			}

			that.scrollTo(x, y, runtime);
		},
		momentum : function(dist, time, maxDistUpper, maxDistLower) {
			var friction = 2.5, deceleration = 1.2, speed = Math.abs(dist) / time * 1000, newDist = speed * speed / friction / 1000, newTime = 0;

			// Proportinally reduce speed if we are outside of the boundaries
			if(dist > 0 && newDist > maxDistUpper) {
				speed = speed * maxDistUpper / newDist / friction;
				newDist = maxDistUpper;
			} else if(dist < 0 && newDist > maxDistLower) {
				speed = speed * maxDistLower / newDist / friction;
				newDist = maxDistLower;
			}
			newDist = newDist * (dist < 0 ? -1 : 1);
			newTime = speed / deceleration;

			return {
				dist : Math.round(newDist),
				time : Math.round(newTime)
			};
		},
		destroy : function(full) {
			var that = this;

			window.removeEventListener('onorientationchange' in window ? 'orientationchange' : 'resize', that, false);
			that.element.removeEventListener(START_EVENT, that, false);
			that.element.removeEventListener(MOVE_EVENT, that, false);
			that.element.removeEventListener(END_EVENT, that, false);
			document.removeEventListener('webkitTransitionEnd', that, false);

			if(that.options.checkDOMChanges) {
				that.element.removeEventListener('DOMSubtreeModified', that, false);
			}

			if(that.scrollBarX) {
				that.scrollBarX = that.scrollBarX.remove();
			}

			if(that.scrollBarY) {
				that.scrollBarY = that.scrollBarY.remove();
			}

			if(full) {
				that.wrapper.parentNode.removeChild(that.wrapper);
			}

			return null;
		}
	};

	function scrollbar(dir, wrapper, fade, shrink, color) {
		var that = this, doc = document;

		that.dir = dir;
		that.fade = fade;
		that.shrink = shrink;
		that.uid = ++uid;

		// Create main scrollbar
		that.bar = doc.createElement('div');

		that.bar.style.cssText = 'position:absolute;top:0;left:0;-webkit-transition-timing-function:cubic-bezier(0,0,0.25,1);pointer-events:none;-webkit-transition-duration:0;-webkit-transition-delay:0;-webkit-transition-property:-webkit-transform;z-index:10;background:' + color + ';' + '-webkit-transform:' + translateOpen + '0,0' + translateClose + ';' + (dir == 'horizontal' ? '-webkit-border-radius:3px 2px;min-width:6px;min-height:5px' : '-webkit-border-radius:2px 3px;min-width:5px;min-height:6px');

		// Create scrollbar wrapper
		that.wrapper = doc.createElement('div');
		that.wrapper.style.cssText = '-webkit-mask:-webkit-canvas(scrollbar' + that.uid + that.dir + ');position:absolute;z-index:10;pointer-events:none;overflow:hidden;opacity:0;-webkit-transition-duration:' + ( fade ? '300ms' : '0') + ';-webkit-transition-delay:0;-webkit-transition-property:opacity;' + (that.dir == 'horizontal' ? 'bottom:2px;left:2px;right:7px;height:5px' : 'top:2px;right:2px;bottom:7px;width:5px;');

		// Add scrollbar to the DOM
		that.wrapper.appendChild(that.bar);
		wrapper.appendChild(that.wrapper);
	}


	scrollbar.prototype = {
		init : function(scroll, size) {
			var that = this, doc = document, pi = Math.PI, ctx;

			// Create scrollbar mask
			if(that.dir == 'horizontal') {
				if(that.maxSize != that.wrapper.offsetWidth) {
					that.maxSize = that.wrapper.offsetWidth;
					ctx = doc.getCSSCanvasContext("2d", "scrollbar" + that.uid + that.dir, that.maxSize, 5);
					ctx.fillStyle = "rgb(0,0,0)";
					ctx.beginPath();
					ctx.arc(2.5, 2.5, 2.5, pi / 2, -pi / 2, false);
					ctx.lineTo(that.maxSize - 2.5, 0);
					ctx.arc(that.maxSize - 2.5, 2.5, 2.5, -pi / 2, pi / 2, false);
					ctx.closePath();
					ctx.fill();
				}
			} else {
				if(that.maxSize != that.wrapper.offsetHeight) {
					that.maxSize = that.wrapper.offsetHeight;
					ctx = doc.getCSSCanvasContext("2d", "scrollbar" + that.uid + that.dir, 5, that.maxSize);
					ctx.fillStyle = "rgb(0,0,0)";
					ctx.beginPath();
					ctx.arc(2.5, 2.5, 2.5, pi, 0, false);
					ctx.lineTo(5, that.maxSize - 2.5);
					ctx.arc(2.5, that.maxSize - 2.5, 2.5, 0, pi, false);
					ctx.closePath();
					ctx.fill();
				}
			}

			that.size = Math.max(Math.round(that.maxSize * that.maxSize / size), 6);
			that.maxScroll = that.maxSize - that.size;
			that.toWrapperProp = that.maxScroll / (scroll - size);
			that.bar.style[that.dir == 'horizontal' ? 'width' : 'height'] = that.size + 'px';
		},
		setPosition : function(pos) {
			var that = this;

			if(that.wrapper.style.opacity != '1') {
				that.show();
			}
			pos = Math.round(that.toWrapperProp * pos);

			if(pos < 0) {
				pos = that.shrink ? pos + pos * 3 : 0;
				if(that.size + pos < 7) {
					pos = -that.size + 6;
				}
			} else if(pos > that.maxScroll) {
				pos = that.shrink ? pos + (pos - that.maxScroll) * 3 : that.maxScroll;
				if(that.size + that.maxScroll - pos < 7) {
					pos = that.size + that.maxScroll - 6;
				}
			}
			pos = that.dir == 'horizontal' ? translateOpen + pos + 'px,0' + translateClose : translateOpen + '0,' + pos + 'px' + translateClose;

			that.bar.style.webkitTransform = pos;
		},
		show : function() {
			if(has3d) {
				this.wrapper.style.webkitTransitionDelay = '0';
			}
			this.wrapper.style.opacity = '1';
		},
		hide : function() {
			if(has3d) {
				this.wrapper.style.webkitTransitionDelay = '350ms';
			}
			this.wrapper.style.opacity = '0';
		},
		remove : function() {
			this.wrapper.parentNode.removeChild(this.wrapper);
			return null;
		}
	};

	// Is translate3d compatible?
	var has3d = ('WebKitCSSMatrix' in window && 'm11' in new WebKitCSSMatrix()),
	// Device sniffing
	isIthing = (/iphone|ipad/gi).test(navigator.appVersion), isTouch = ('ontouchstart' in window),
	// Event sniffing
	START_EVENT = isTouch ? 'touchstart' : 'mousedown', MOVE_EVENT = isTouch ? 'touchmove' : 'mousemove', END_EVENT = isTouch ? 'touchend' : 'mouseup',
	// Translate3d helper
	translateOpen = 'translate' + ( has3d ? '3d(' : '('), translateClose = has3d ? ',0)' : ')',
	// Unique ID
	uid = 0;

	// Expose iScroll to the world
	$kit.iScroll = iScroll;
})();
